This application claims the priority benefit of Taiwan application serial no. 90115213, filed Jun. 22, 2001.
1. Field of the Invention
The invention relates to a packaging structure. More particularly, the present invention relates to a leadframe packaging structure that integrates passive devices.
2. Description of the Related Art
To eliminate negative electrical effects such as electro-magnetic interference or undesirable coupling between leads in a leadframe packaging structure, passive devices are conventionally arranged on the leadframe of the leadframe packaging structure.
Referring to FIG. 1, a top view schematically illustrates a conventional leadframe structure used in packaging structures that integrate passive devices. At a central chip-bonding region 102 of the leadframe 100, a die pad 104 is conventionally arranged to carry a chip 106. Tie bars 108 are arranged around the die pad 104 as support elements to prevent warping of the die pad 104 during an encapsulating process. The leadframe 100 further comprises leads 110 around the die pad 104 and dam bars 116. The dam bars 116 define an encapsulating region 117 by separating the leads 110 into inner leads 112 and outer leads 114.
FIG. 2 is an enlarged view of the region 118 shown in FIG. 1. As shown in FIG. 2, two adjacent inner leads 112a are conventionally extended to form a contact pad 120. Supported by two leads 112a, the contact pad 120 is more rigid. Furthermore, a peripheral portion of the die pad 104 extends outwardly to provide another contact pad 122. A passive device 124 thereby can be conventionally mounted between and electrically connects the contact pads 120, 122. The leadframe thus arranged can integrate a passive device within a packaging structure to improve the electrical proprieties of the packaging structure.
However, because the space between the die pad and inner leads of the conventional leadframe is limited, the possibility of passive device arrangement on the conventional leadframe is also limited. Such a space limitation allows for a decoupling of only two adjacent leads and more distant leads cannot be decoupled.
An aspect of the present invention is to provide a leadframe packaging structure that integrates passive devices and overcomes the above problems by rearranging the leadframe structure.
To attain at least the foregoing objectives, a packaging structure integrating passive devices comprises, according to an embodiment of the present invention, a leadframe, a chip, at least a passive device, and an encapsulant material. The leadframe comprises a plurality of first leads that define a chip-bonding region within the leadframe. A die pad is arranged in the chip-bonding region. The chip is bonded on the die pad. A plurality of second leads extends and terminates in a plurality of contact pads in the chip-bonding region. An adhesive tape may be bonded onto bottom surfaces of the contact pads. At least a passive device is mounted between and electrically connects the contact pads. A plurality of bonding wires electrically connects the chip, the passive device, and the first and second leads to one another. The encapsulant material encapsulates the chip, the bonding wires and the passive device, and leaves an outer portion of the leads exposed.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.